THE 



SOIENTfflO PROCEEDINGS 



---»^. juao''^ 



OF 



THE ROYAL DUBLIN SOCIETY 



A CEYOSCOPIC METHOD FOE THE ESTIMATION OF SUCEOSE. 



By HENEY H. DIXON, Sc.D., F.E.S., 

 University Professor of Botany in Trinity College, Dublin ; 



AND 



T. G. MASON, M.A., Sc.B.i 



Eead DECEirBuii 16, 1919. Published January 9, 1920. 



The depression of freezing-point caused by a given qnartity of sucrose in a 

 given volume of water is approximately doubled after inversion. It is 

 evident, therefore, that by two cryoscopic observations — before and after 

 inversion — the sucrose-content of a solution can be determined. By using 

 the Thermo-electric Method of Cryoscopy (2) the estimation can be effected 

 on small amounts of fluids, and^ as the presence of colloids introduces no 

 difficulties, it should furnish a rapid and sufficiently accurate means of 

 estimating the sucrose-content of physiological fluids. 



The following investigation was undertaken to work out the details of 

 the method, and to test its applicability to plant saps. 



' Mr. Mason was enabled by a maintenance grant from the Department of Researcli 

 to engage in this research. 



SCIENT. PEOC. K.D.S., VOIi. XVI, NO. I, B 



